Lower alkylthiomethylene containing phenols

ABSTRACT

Mono and dimethylene thioethers of dialkyl phenols are prepared by reacting dialkyl phenols at elevated temperatures with formaldehyde and the respective mercapto compound in an inert solvent in the presence of an alkaline compound.

United States 'atent Eggensperger et al.

LOWER ALKYLTHIOMETHYLENE CONTAINING PHENOLS Inventors: HeinzEggensperger, Gadernheim, upper Bensheim, Volker Franzen. Heidelberg;Gerd Hiihner. Schoplheim am Baden; Dieter \Voltjes. Bensheim amBergstrasse. all of Germany Assignee: Ciba-Geigy AG. Basel. SwitzerlandFiled: Apr. 21. 1970 Appl. No.: 28,275

Related US. Application Data Continuation of Ser. No. 714.094. March 18.1968. abandoned.

Foreign Application Priority Data Mar. 17. 1967 Germany 52554 US. Cl.260/609 F; 252/404; 260/4595 Int. CL" C07C 149/36 Field of Search260/609 F Reid. Chemistry of Bivalent Sulfur". ll. l7 (1960). Walker.Formaldehyde.". 3rd. Ed.. 3 l0-3l5. (I953 Primary E.\'(IHI/II(IElbIt L.Roberts Asxismm ExmninerD. R. Phillips Attorney. Agent. or FirnzFisher.Christen & Sahol [57] ABSTRACT Mono and dimethylene thioethers ofdialkyl phenols are prepared by reacting dialkyl phenols at elevatedtemperatures with formaldehyde and the respective mercapto compound inan inert solvent in the presence of an alkaline compound.

1 Claim. No Drawings LOWER ALKYLTHIOMETHYLENE CONTAINING hyde andmercapto compound must be employed.

v PHENOLS 'lnste ad' of formaldehyde, compounds developing Thisapplication is a continuation of application Ser. formaldehyde under thereaction Conditionssuch as 714094 fil d M '18 1968 ov' Abandonedparaformaldehyde or hexamethylene tetramine, can be The inventionrelates to the preparation and use of Usedaromatic methylene thioethers.Suitable inert solvents are, e.'g., lower alcohols such Such compoundscorrespond to the formulae 1 as methanol, ethanol, propanol',isopropanol, and diols OH CH I OH R] 1 R 56/01 92 RVXCHQSR S R2 CH SR 12CH SR wherein I and polyols' and their ethers such as ethylene glycol,di- R and R are the same or different linear or 70 ethylene glycol, andethyleneglycolmonomethylether.

b h alkyl g p ng 1 t0 6 C atoms, It is a particularadvantage of ourprocess that it is not 3 linear or Ched alkyl group which mayconnecessary to use the preformed mercapto compound; tam Oxygen orSulfur ether lmkage 0T whlch may it is'sufficient to form said compoundin situ from the be substituted y y y or is an alkylene readilyavailable alkyl halide and hydrogen sulfide in group (in the formationof Symmetrical his P the presence of alk'alimetal hydroxide and to reactit nols). 7 directly, without isolation, with the dialkyl phenol andThe'compounds are useful for the Stabilization formaldehyde. It issurprising that, in this procedure,

game compounds and materials against deterioration the mercap-toCompound reacts substantially the of 5: f T pletely with the dialkylphenol and formaldehyde to i zi s g sg x Combmanon Wnh other dmmxl''form the recited compounds without interference from compou'nds offormula I have p the also present alkali sulf de ln addition, thisprocepared y reacting h corresponding Mannich bases dure eliminates theloss which is unavoidable when the mercapto compound has'to be firstisolated from the reaction mixture; such loss may amount up to 10%.

The preparation of dialkyl phenols containing sulfur c zm s) I-containing groups in 0 and/or 1 position according to the invention ispreferably as follows: To the solution of 0.] to 1 moles of a base,preferably sodium or potassium hydroxide, in an organic solvent such asa lower or benzyl chlorides with the respective mercaptides. 40 alcohol,polyether, or the like, there are added sequen- We have found a verysimple one-step method for the tially l or 2 moles of the mercaptocompound (dependpreparation of Such compounds which not Only allows ingon whether one or two sulfur containing groups of Obtaining yields whichare about 10 higher than shall be introduced into the phenol), 1 mole ofthe althose obtained the known method but is phenol and to 2 or to 4,moles of formalso suitable to produce compounds of the formula IIIa1dehydc f ald h d or f ld h d 1 which, We believe have evr beenpreparedbeforetion. The reaction mixture is refined for l to 5 hours Inaccordance with the invention, dialkyl phenols of in a nitrogenatmosphere and, after cooling, neutralized the formula e.g. with aceticacid. The solution is then concentrated 50 in vacuo, and the residue isextracted with ethyl ether.

OH The reaction product, remaining after the ether has I g z (Iv) beendistilled off, can be further purified by recrystallization.

in the modification of the invention where the mer- 2 I capto compoundis formed in situ in the reaction vessel,

a suitable procedure is as follows:

Into a solution of l to 2 (or 2 to 4) moles of alkali metal hydroxide ina suitable solvent, preferably ethanol or isopropanol, there isintroduced at a temperature of 0 to 20C hydrogen sulfide until thesolution is satu- HSR rated therewith; subsequently, l (or 2) mole ofalkyl halide are added dropwise, and after the addition of the alkylhalide is terminated, the reaction mixture is mainin an inert solvent inthe presence of a base, preferably tained for a further hour at atemperature of to alkali metal hydroxide. 70C. Then, nitrogen is passedthrough the solution, 0.7

For the preparation of compounds of the formula III, to 1 moles ofalkylated phenol and 1.2 to 2 (or 2.4 to of course twice the equivalentamounts of for'malde- 4) moles of formaldehyde are added, the reactionmixare reacted with at least the stoichiometric amounts of formaldehydeand a mercapto compound a ture is refluxed for 1 to hours and processedas described above.

The yields are in the range of 80 to 99 7c, calculated on dialkylphenol.

The -IR spectrum and elementary analysis (5 calc. 7.6%. found 7.2%)confirm that the obtained product is lauryl-(3.5-di-tert.butyl-2-hydroxyrbenzyl) sulfide.

EXAMPLE 3 The invention will be illustrated but not limited by 5 Asolution of 45 g (0.8 moles) of potassiumhydroxthe following examples.ide in 250 cc of ethanol was saturated at C with hy- EXAMPLE 1 drogensulfide. 47 g (0.25 moles) of l.2- l g mOlCS) Of Sodium hydroxide WBICdiSSOlVCd dibromoethane were added dropwise. and the mixture in 200 ccof cthyleneglycol monoethylether. To said so- H) a h m d at 6()-7()C for1 hour. After cooling, nitrolution. here C ll l ill 1 g -4 m l s) of genwas passed through the reaction solution. and 82.4 methylmcrcaptan. ()4cc of a formaldehyde solug 04. l f 2 6-di-tert butylphcnol and 80 cc ofa tion m l of form dehyd and g 4071 aqueous formaldehyde solution 1mole) were moles) of 2.4-di-tert.butylphenol. The obtained mixdd t Thmixture was r fl x d f 2 hours d ture was slowly heated to boiling in agentle nitrogen 15 cesscd as i Example 1. current. Af er 2 h ur h mix re11 l ncuirkll- After recrystallization from methanol, there were obizedwith glacial acetic acid. evaporated to dryness in mi d 102 g f 1 2-bi 35 di h 4 vacuo. and the residue was extracted with ether. Thehydroxybenzylmcrcupto) ethane (m 143 144C ether was distilled off. andthe residual product was reresponding to a i ld f 967 alculated onphenol. crystallized twice from methanol. There were obtained 30 S I12.1 7 f nd 1 1,771, 88 g of methyl-( 3.4-di-tert.butyl-2j-hy(iroi y benayl) sul: EXAMPLE 4 fide. having a melting point of 44 -46 C. The yieldas 83 p r m Of e y- To a solution of4 g (0.1 mole) of sodium hydroxide.

EXAMPLE 2 there were added sequentially 27 g (0.3 moles) of n- Hydrogensulfide was passed at 20C into a solution butylmcrcapmm 1 4 g 1 molc) fb 1 of g (08 moles) of Potassium hydroxide in 350 CC cresol and 32 cc ofaqueous formaldehyde solution (0.4 of ethanol until the solution wassaturated. Subsemoles). Th mixture was heated to boiling in a gentle qy- L moles) of 'y Chloride were nitrogen current for 5 hours and thenprocessed as in added. and the mixture was heated for 1 hour at to 30Example 1 C. After cooling. nitrogen was passed through the There wereObtained 294 g 0% f theory) f 2 4- solution and 82.4 g (0.4 moles)of2.4-di-tert.butyl phebisbuty] b 1 3 1 h nol and 64 cc of aformaldehyde solution (0.8 moles of (H- O) were added. The mixture wasrefluxed for 2 S C1110 1747 f d 1 hours. and then processed as describedin Example 1. qg An oil is obtained which can be recrystallized from aEXAMPLES 5-22 methanol ethanol mixture at -3()C. Yield per cent Thecompounds of Tables l-lll were prepared in a of theory. calculated onthe phenol. similar manner as shown in the preceding examples.

TABLE I OH 1 2 Compounds of formula I CH SR S S Ex. R, R R melting yieldcale. found point "/1 "/1 5 --tert.hut \-l CH. CH 73-75C 90 14.3 l4.6 6tert.hut \l tert.hut \l CH. ,CH. '()H 5255C 97 l().l'l 9.9 7 lert.hutyltert.hutyl ((H. ,SC|.;H;\ 4345C 11.9 l2.l

ten. butyl H tcrl.hut \'l tert.hutyl -(H. .CH --SCH Q0? l43l44C )(i [2.]I [.4

lert. bulyl tert. butyl u -tert.hutyl tert.hut \'l CH. s-CH. Q-0H7()-73C 87 my ms t er t butyl fe r t but yl lU -tert.hutyl (.H;, CH..CH. .S CH. QM! I2'-)l3lC 98 H5 11.

te r t but yl CH 11 -CH CH (CH. ,SCH. H l4() l42( 72 17.7 18.]

l2 CH;, CH;. OH2CH2OH (13-65% 7a 15,1 15.3 13 isopropyl isopropyl CH,CH. ,-O-CHH oil 70 l 1.? l l K) TABL E I I i Compounds of formula II CHSR S 5 Ex. R R. R physical yield cale. found properties 'i ll 14lerl.hutyl tcrt.but \l (H m 4+ 4N1 s3 |.:.u 13 tert.but \l -CH; (H hV3.95 N5 14.3 14.4 lb tert.but \'l tert.bul \l .H v i l \iil, n)?" 1502)X0 7.h 7."

l7 tert.bul \l tert.but \l CH -CH- .SCH ll$7( 7) 1 UN 13 1 OH Toble in Rg sn Compounds of formula lll CHQSR3 Example R, R R physical yield 5calc. 5 found properties '2 1 Ill -tert.buty1 m 8N-90C 70 22.6 21.9

:2 -CH m43'-- 15( 7: 1m 11.3

The compounds obtained by the process of the inven- EXAMPLE 23 tion aregood stabilizers for polystyrene resirisfesters. and synthetic oils suchas polymer oils against their deterioration by oxygen. light. and heat.

Examples ofpolystyrene resins which can be thus stabilized, are impactresistant polystyrene resins, copolymers of butadiene and styrene. ABSresins. MBS resins. and SAN resins. Esters stabilized by the compoundsare. e.g.. phthalic esters used as plasticizers, or polyesters such asdicarboxylic acid diol condensation products. I

Particular good stabilization has been observed with compounds of therecited formulae in which R is tert- .butyl and R methyl.

The compounds of the invention show a greater stabilizing effect thanthe phenyl derivatives used heretofore for this purpose, such asZ.o-di-tert.butyl-p-cresol or the hydroxy-alkylphenyl alkanoic acidesters disclosed in the German DAS No. 1.201.349. Th'stabilizing effectcan be still further improved by the use of additional stabilizers.particularly organic phosphites such as trisnonylphenyl phosphite.

The novel stabilizers are generally applied in amounts of 0.01 to 10 7rby weight of the organic substance to be stabilized.

The following examples are given to illustrate the use of the compoundsprepared according to the invention as stabilizers. All parts are givenby weight unless indicated otherwise.

All the tests hereinafter set forth in Table IV were :madewith the sameABS polymer which had the approximate composition by weight of 5%acrylonitrile.

15C: butadiene. and 8071 styrene. Test samples were prepared by hotmilling at about C for 10 minutes compositions containing 100 parts ofthe ABS resin, 1 partof a lubricant 1,2-bis-stearoyl amino ether) and0.5 parts of the stabilizer. The obtained films were pressed under apressure of 200 atm. and a temperature of C to plates of 1 mm thickness.which were cut to strips and placed in a drying cabinct'at a temperatureof 100C for accelerated ageing. The stabilizing efficienc'y was measuredbythe change of color and brittleness of the strips. The followingresults were obtained.

7 EXAMPLE 24 Stabilization of an MBS Resin The tests listed in Table Vwere made with the same MBS polymer which had the approximatecomposition by weight of 16% methacrylic acid ester. 80% but-adiene, and4% styrene.

Test samples were prepared by hot milling at l7()C for 10 minutes theresin compositions containing the stabilizer and pressing the obtainedfilms in a platen press under a pressure of 200 atm. at a temperature of190C to plates of l mm thickness which were cut into strips and aged ina drying cabinet at 90C.

The stabilizing effect was determined by the color changes andbrittleness of the strips. The following results were obtained.

Stabilization of lmpaet Resistant Polystyrene The impact resistantpolystyrene was a blend of 88 parts of polystyrene and I2 parts of abutadiene-styrene eopolymer which contained as stabilizer 1.271 oftrisnonylphenyl phosphite. 12 g each of said copolymer were plasticizedon a laboratory roller mill at 175C, then 150 mg of the stabilizerlisted in Table V]. and subsequently 88 g of polystyrene were added. andthe blends were hot milled at l75C for minutes and at 180C and 200atmospheres pressed to plates which were cut into 5 strips and stored ina drying cabinet at 85C. The stabilizing effect was determined by thetime of beginning brittleness of the samples.

EXAMPLE 26 Stabilization of Dioctyl Phthalate Blends of 3 g each wereprepared from dioctyl phthalate and the stabilizers of Table VII. Theblends were heated in a closed vessel under oxygen at 192C.

The time was determined after which the plasticizer took up oxygen andthe pressure had dropped by 20 torr. Said oxygen absorption indicatesthe start of the degradation.

The table shows that the stabilizers of the invention are superior toconsiderably larger amounts of the well known stabilizer bisphenol A.

EXAMPLE 27 Stabilization of Polymer Oil Mixtures of 3 g each wereprepared from a copolymer of ethylene and polyisobutanol with 0.2 percent of the stabilizers listed in Table Vlll and their oxygen absorptionwas determined as in Example 26.

TABLE Vlll Stabilizer Pressure drop by 10 torr after bisphenol A l hourminutes 2 hours 3t) minutes 4 hours 2 hours 50 minuteslh-di-tert.butyl-p-cresol stabilizer of example I l stabilizer ofexample 14 We claim: l. As new composition of matter, compounds of theformula CH SR H SR wherein R and R are selected from the groupconsisting of methyl, isopropyl and t-butyl, R is selected from thegroup consisting of a straight or branched-chain member of the groupconsisting of alkyl, and alkylene having one to three carbon atomswherein only one of

1. AS NEW COMPOSITION OF MATTER, COMPOUNDS OF THE FORMULA